Make Your Own Fish Fertilizer

Remember that old story of the natives teaching the Pilgrims to bury fish beneath their corn plants? It works. That’s why “fish emulsion” or “fish fertilizer” is still sold as a common organic fertilizer. Plants love it – and you can make it yourself. This is a good thing, because fish emulsion is really expensive.

A few weeks ago a couple of friends came over for a major yard work day. Both of these guys are pretty hard-core plant geek/survivalist/homesteader types.

When they arrived, one of them said, “Hey… I brought you a little gift from the Caribbean market.” He then proceeded to haul two buckets of nice fresh fish guts and parts from the back of his truck.

I was thrilled. What thoughtful friends I have! Once I had this bounty… it was time to make it into something amazing for my plants.

If you have access to fish waste, you can do the same thing I do. It’s easy and it smells incredible. Here’s how I’m doing it.

Step 1: Get A Big Barrel

After this particular project, you’re not going to want to use this barrel for anything else, so choose wisely. I got a great used 55-gallon drum with a top from the local feed store:


You want a lid for this thing to make sure animals stay out and that none of the fish turn into undead zombie fish and escape in the night. They’ll come in your windows and stuff, trashing your house and eating your brains. Don’t let that happen.

Step 2: Throw In The Guts!


Isn’t that an amazing picture? I think that should be the cover of a punk album. Or maybe something by Aphex Twin. You can almost smell the ocean. I threw in crab parts, too, since they’re loaded with calcium and other nutrients. I don’t know how well they’ll break down in the final scheme of things, but I imaging they’ll go eventually.

Step 3: Add Some Carbon!

We all know about the whole C:N part of composting, right? That is, for nitrogenous material, it helps to add some carbon so the microorganisms get plenty to snack on as they break down a pile. I’m doing the same thing with my fish fertilizer. In this case, I used shredded moringa tree trunks.


You’d never know there was a hellish slop of yucky piscine waste beneath that, would you? Looks pretty innocuous, if I do say so myself. You could probably use sawdust, mulch chips, shredded paper or straw in this mix… the idea is just to give a little more balance to your fertilizer. We’re anaerobic composting, here… it may be a nasty wharf-scented slop, but it’s still compost.

Step 4: Pour Some Sugar On Me

Actually, we’re pouring sugar in the bucket of horrors. This adds even more carbon, plus gives the bacteria a nice headrush. I have a gallon of livestock molasses I use for projects like this (and on my oatmeal). I like to imagine it has more micronutrients in it, though I have no idea. Drop in a few sloppy blubs, like so:

HomemadeFishFertilizer3Yum. Have at it, microorganisms. Now… there’s just one more step to do. I call it “Step 5.” And… here it is:

Step 5: Make It Into Soup

Grab your hose and add a generous amount of water to the mix. I added about 25 gallons. That’s enough to keep everything nice and wet while it rots down. I took a photo in case you’ve never filled a container with water before:


See? Easy! Now comes the hard part… waiting. Some sites will recommend you stir this fetid elixir now and again. I think that’s a good idea, since it gets some oxygen in there and mixes everything up. Just know this: eventually, it will rot down. Bit by bit, the yuckiness will subside and you’ll end up with a rich, fish-sauce smelling fermented brew that plants adore. Though this is the first time I’m attempting this kind of composting with fish waste, I have make anaerobic compost in barrels before… and the secret is time. As a final note, this mixture is loved by more than just plants – I had vultures land within an hour of this project. They smelled the empty fish gut buckets. Sorry, guys – no soup for you!

One other thing: this is going to be strong stuff. Make sure you thin it out with plenty of water before applying to plants.

Also, I’m not going to use this stuff on my salad greens… but I will be thinning it out and watering my corn, my fruit trees, my blueberries (before the blueberries ripen) and other plants that don’t go directly into my mouth.

My Grandpa was a sailor and I’ve always loved the ocean… I’m just not quite crazy enough to consume rotten fish. Unless you paid me at least enough $$$ so I could buy my own stomach pump. Then I might consider it.

Until then, keep your eyes open: there are many, many ways to compost and re-use things that would otherwise be completely wasted. I’d much rather feed these fish to my plants than have them end up in a landfill. You’re turning trash into treasure, even if the process is a little less than savory.

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About David The Good

David The Good is a naturalist, author and hard-core gardener who has grown his own food since 1984. At age five, he sprouted a bean in a Dixie cup of soil and caught the gardening bug. Soon after, his dad built an 8’ by 8’ plot for him and David hasn’t stopped growing since. David is the author of four books, writes a regular column for The Ag Mag in North Central Florida, is a Mother Earth News blogger and has also written for outlets including Backwoods Home, Survival Blog and Self-Reliance Magazine. You can find his books on Amazon here. David is a Christian, an artist, a husband, a father of seven, a cigar-smoker and an unrepentant economics junkie who now lives somewhere near the equator on a productive cocoa farm. Visit his daily gardening and survival blog here: The Survival Gardener And for lots more gardening info, click here and subscribe to his often hilarious YouTube channel.

View all posts by David The Good

10 Responses to “Make Your Own Fish Fertilizer”

  1. Kym Says:

    This is exactly what I needed! It was well laid out and had easy-to-follow instructions. I do have a couple of questions. Can I put a lid on it? Do you have a guess-timate of how much of a waiting time? Again, thanks for a great article.


  2. Sandy Says:

    Is this an anaerobic or aerobic type of composting? The reason I ask is because I have some bokashi serum I was thinking of adding to it. If it’s aerobic I would think that is not a good idea.


  3. Rudy Says:

    Thank you Dave,
    Outstanding explanation. Simple and straight to the point. The pictures were incredibly helpful. You have the gift of teaching.
    May the Lord bless you.


  4. George K Joseph Says:

    I really appreciate the richness of your article.
    Thank you Goodman


  5. Elfriede Nichols Says:

    Perfect, I just discovered that some fish in my freezer is freezer burned, and I didn’t just want to throw it out.


  6. Nonar Says:

    Since we are very far from any fish resource can we use
    sardines from a can.



  7. Mike D. Says:

    Where did you get the fish guts, etc?


  8. Gregg Hochderffer Says:

    Howdy everyone. If you need fish for fertilizer and live within 200 miles of Sioux City IA, I can deliver 1/2 a ton or more of carp. You will need a lot of barrels! Call 712-490-0147 if interested.


  9. Linsy Says:

    Precise instructions and funny too.. Thanks! I am going to get to the disgusting process right away. I have prawn waste sitting in a bowl wondering about its destiny..


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